Projector device

ABSTRACT

A liquid crystal projector device of the present invention includes a lamp unit and a lamp cooling fan, the lamp unit having disposed therein a columnar lamp bulb having a luminous body enclosed therein, the lamp unit having a side wall opposed to the lamp cooling fan and provided with a first and second air introduction openings at opposite sides of a plane including a central axis of the lamp bulb and perpendicular to the side wall, for introducing the air drawn from the lamp cooling fan toward the lamp bulb.

The priority application Number 2005-262887 upon which this patentapplication is based is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a projector device adapted to guidelight from a light source to an optical system to generate image lightfor magnification projection on a forward screen.

2. Description of Related Art

A conventional projector device of this type includes a casing havingdisposed therein a light source and an optical system including apolarization beam splitter, a polarizing plate, liquid crystal panels, aprojection lens, etc. A discharge emission lamp unit such as a halogenlamp and a metal halide lamp is used as the light source.

The lamp unit includes a lamp and a reflector for reflecting lightemitted from the lamp toward the optical system. The lamp is formed byenclosing a luminous body inside a quartz bulb. The lamp is cooled by alamp cooling fan because the lamp has a shortened life when the lamp hasa temperature exceeding a limit temperature.

It is known that in light emission of the lamp, the temperature at thevertically upper side of the quartz bulb is higher than the temperatureat the lower side thereof, which results in the temperature differencebetween above and below the quartz bulb. This temperature differencebetween above and below is the greatest at the position where theluminous body is enclosed in the quartz bulb. In order to fully bringout the performance of the lamp, it is necessary to maintain thetemperature of the lamp below the limit temperature, as well as to coolthe lamp such that the temperature difference between above and below isheld within a certain range.

Accordingly, there has been known a projector device having an airintroduction opening for introducing air drawn from the lamp cooling faninto the lamp unit, which is provided at the vertically upper side ofthe lamp unit such that the air hits the vertically upper side of thequartz bulb (see JP 7-281296, A).

However, if the above projector device is set by being hung from aceiling, then the setting of the device will be vertically reversed.Consequently, the air introduced from the air introduction opening willhit the vertically lower side of the quartz bulb.

In this case, the vertically lower side of the quartz bulb isexcessively cooled, which results in an increased temperature differencebetween the vertically upper and lower sides of the quartz bulb.Therefore, there has been a problem in that the above projector devicecannot be set by being hung from a ceiling.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a projector device inwhich the cooling effect for the vertically upper side of a lamp and thecooling effect for the vertically lower side of the lamp areapproximately constant regardless of the setting of the device.

A projector device of the present invention includes a lamp unit 7providing a light source, a cooling fan 190 for cooling the lamp unit 7,and an optical system for generating color image light with the lampunit 7 providing the light source, the lamp unit 7 including a columnarlamp bulb 170 having a luminous body enclosed therein, and a reflector71 for reflecting light emitted from the lamp bulb 170 toward theoptical system, and is capable of taking a plurality of set posturesincluding a first set posture where the lamp bulb 170 of the lamp unit 7extends approximately horizontally, and a second set posture where thelamp unit 7 is rotated on the lamp bulb 170 by 90 degrees from the firstset posture.

A first air introduction opening 74 a and a second air introductionopening 74 b are provided in a side wall of the lamp unit 7 opposed tothe cooling fan 190 and at opposite sides of a plane including a centralaxis of the lamp bulb 170 and perpendicular to the side wall, and airdischarged from the cooling fan 190 is blown to the lamp bulb 170through the both air introduction openings 74 a, 74 b.

When the above projector device of the present invention is set in thefirst set posture, that is, when the projector device is set on ahorizontal table, the air drawn from the lamp cooling fan 190 isforcibly separated by part of the side wall of the lamp unit 7intervening between the first air introduction opening 74 a and secondair introduction opening 74 b, so that the air introduced from the firstair introduction opening 74 a will flow above the lamp bulb 170, and theair introduced from the second air introduction opening 74 b will flowbelow the lamp bulb 170.

On the other hand, when the projector device is set in the second setposture, that is, when set by being attached to a vertical wall opposedto a screen, the air drawn from the lamp cooling fan 190 is forciblyseparated by part of the side wall of the lamp unit 7 interveningbetween the first air introduction opening 74 a and second airintroduction opening 74 b, so that the air introduced from the first airintroduction opening 74 a and second air introduction opening 74 b willflow through both right and left sides of a light emitting portion 172of the lamp bulb 170.

Therefore, the air drawn from the lamp cooling fan 190 will not bevertically blown to the vertically lower surface of the lamp bulb 170 inany of the above set postures. This prevents the low-temperature,vertically lower side of the light emitting portion 172 of the lamp bulb170 from being excessively cooled. Consequently, the temperaturedifference between the vertically upper side and vertically lower sideof the lamp bulb 170 can be held within a certain range regardless ofthe setting of the device.

In a specific configuration, the first air introduction opening 74 a andthe second air introduction opening 74 b are open toward the lightemitting portion 172 of the lamp bulb 170 having the luminous bodyenclosed therein, and a third air introduction opening 73 open toward anend of the lamp bulb 170 is provided between the first and second airintroduction openings 74 a, 74 b in the side wall of the lamp unit 7.

The specific configuration not only allows the highest-temperature lightemitting portion 172 of the lamp bulb 170 to be cooled by the airintroduced from the first and second air introduction openings 74 a, 74b, but also enables the end of the lamp bulb 170 to be cooled by the airintroduced from the third air introduction opening 73.

As described above, according to the projector device of the presentinvention, the cooling effect for the vertically upper side of the lampand the cooling effect for the vertically lower side of the lamp areapproximately constant regardless of the setting of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a liquid crystal projector device of thepresent invention;

FIG. 2 is an exploded perspective view of the liquid crystal projectordevice;

FIG. 3 is a perspective view showing the liquid crystal projector devicewith an upper half case thereof removed therefrom;

FIG. 4 is an exploded perspective view of a cooling unit;

FIG. 5 illustrates an optical system and an image synthesizer;

FIG. 6 is a perspective view of a diaphragm mechanism;

FIG. 7 is an exploded perspective view of the diaphragm mechanism;

FIG. 8 includes state transition diagrams of the diaphragm mechanism;

FIG. 9 illustrates areas of light irradiated on a second integrator lenswhen the diaphragm mechanism is set in respective states shown in FIG.8;

FIG. 10 illustrates luminous flux blocking states of the diaphragmmechanism;

FIG. 11 is a perspective view of an optical compensation sheet holder;

FIG. 12 is an exploded perspective view of the optical compensationsheet holder;

FIG. 13 illustrates changes in an attachment posture of the opticalcompensation sheet holder in the case of adjusting the attachmentposture of the optical compensation sheet holder with a first adjustmentoperation;

FIG. 14 illustrates changes in an attachment posture of the opticalcompensation sheet holder in the case of adjusting the attachmentposture of the optical compensation sheet holder with a secondadjustment operation;

FIG. 15 is a front view showing a horizontal moving range of a lensshift mechanism;

FIG. 16 is a front view showing a vertical moving range of the lensshift mechanism;

FIG. 17 is an exploded perspective view of the lens shift mechanism;

FIG. 18 is an exploded perspective view enlargingly showing a cylinder,a vertical drive mechanism and a horizontal drive mechanism shown inFIG. 17;

FIG. 19 is an exploded perspective view enlargingly showing a stationarybase and a movable member shown in FIG. 17;

FIG. 20 is a perspective view showing a lock mechanism of the lens shiftmechanism;

FIG. 21 is a side view showing the lock mechanism;

FIG. 22 illustrates the vertical drive mechanism locked or unlocked bythe lock mechanism;

FIG. 23 illustrates the horizontal drive mechanism locked or unlocked bythe lock mechanism;

FIG. 24 illustrates a change of how a click-feeling generation mechanismis engaged with the horizontal drive mechanism;

FIG. 25 illustrates a change of how a click-feeling generation mechanismis engaged with the vertical drive mechanism;

FIG. 26 is a perspective view of a lamp unit;

FIG. 27 is an exploded perspective view showing a frame and a concavelens of the lamp unit;

FIG. 28 is a perspective view showing the lamp unit attached to the leftend of an optical system holding case;

FIG. 29 is a perspective view showing an attachment structure forattaching the lamp unit to the left end of the optical system holdingcase;

FIG. 30 is a perspective view showing an attachment structure forattaching a flat spring member to the left end of the optical systemholding case;

FIG. 31 is a sectional view showing the lamp unit attached to the leftend of the optical system holding case;

FIG. 32 illustrates fitting pins of the lamp unit having ends thereofinserted into positioning holes, and the lamp unit attached to the leftend of the optical system holding case;

FIG. 33 includes enlarged sectional views showing deformations of theflat spring member in the state where the fitting pins of the lamp unithave the ends inserted into the positioning holes, and in the statewhere the lamp unit is attached to the left end of the optical systemholding case;

FIG. 34 is a sectional view showing an internal structure of the lampunit;

FIG. 35 includes front and back perspective views of the concave lens;

FIG. 36 is a perspective view showing an attached channel housing;

FIG. 37 is a perspective view showing an attached air filter;

FIG. 38 is an exploded perspective view showing an attachment structureof the channel housing and air filter;

FIG. 39 illustrates flows of cooled air in the lamp unit in the statewhere the liquid crystal projector device of the present invention isset in four different setting postures;

FIG. 40 illustrates a flow of cooled air in the lamp unit in ordinaryuse, and a flow of air in the lamp unit in a lamp bulb explosion;

FIG. 41 illustrates light paths through the concave lens, firstintegrator lens, second integrator lens and a slit plate to apolarization beam splitter;

FIG. 42 illustrates arc images formed on a plurality of cellsconstituting the central portion of the second integrator lens in thecase of using the concave lens of the present invention, and arc imagesformed on a plurality of cells constituting the central portion of thesecond integrator lens in the case of using a conventional concave lens;

FIG. 43 illustrates arc images formed on the polarization beam splitterin the case of using the concave lens of the present invention, and arcimages formed on the polarization beam splitter in the case of using aconventional concave lens;

FIG. 44 is a control block diagram showing a configuration for detectingclogging of an air filter;

FIG. 45 is a graph showing a relationship between outside airtemperatures and revolutions of a cooling fan;

FIG. 46 is a graph showing a relationship between revolutions of thecooling fan and reference drive voltages Vref, and a relationshipbetween revolutions of the cooling fan and drive voltages where it isdetermined that the air filter is clogged; and

FIG. 47 is a flow chart showing a control procedure to be performed by amicrocomputer in detecting clogging of the air filter.

DETAILED DESCRIPTION OF THE INVENTION

The present invention embodied in a liquid crystal projector device willbe specifically described below with reference to the drawings. In thedescription given below, the image projection direction of the liquidcrystal projector device shown in FIG. 1 is defined as the forwarddirection, and right and left are defined by facing the front face ofthe liquid crystal projector device.

Overall Construction

As shown in FIG. 1, the liquid crystal projector device of the presentinvention includes a flat casing 1 including an upper half case 11 and alower half case 12. The casing 1 has a surface thereof provided with anoperation portion 13 including a plurality of operation buttons and awarning portion 15 including a plurality of warning lights, while thecasing 1 has a front face thereof provided with a projection window 14.The projection window 14 has a projection lens 20 exposed therefrom.

As shown in FIG. 2, the casing 1 has an interior provided with asynthetic resin optical system holding case 30 extending in anapproximate L-shape. The optical system holding case 30 has a lamp unit7 providing a light source attached to the left end thereof. Alsoattached to the forward end of the optical system holding case 30 is alens shift mechanism 2 for horizontally and vertically reciprocatinglymoving a projection lens system including the projection lens 20 and acylinder 21 for holding the projection lens 20.

Exposed to the right side wall of the casing 1 are, as shown in FIG. 1,a horizontal operation dial 24 for horizontally reciprocatingly movingthe projection lens system, a vertical operation dial 28 for verticallyreciprocatingly moving the projection lens system, and a knob 134 of alever member 133 for fixing the projection lens system in a desiredposition.

As shown in FIG. 3, the optical system holding case 30 has a slitopening 320 provided at the left end thereof. Inserted in the opening320 is a diaphragm system 5 for regulating the amount of light to beincident on liquid crystal panels for respective colors 43 b, 43 g, 43 rdepending on input data for a projection image in order to improve acontrast of the projection image.

A lamp cooling fan 190 for cooling the lamp unit 7 is placed between therear wall of the lower half case 12 and one side wall of the lamp unit 7opposed thereto. An exhaust fan 191 is placed in the left middle of thelower half case 12, with an inlet direction thereof toward the lamp unit7.

Disposed inside the optical system holding case 30 are an optical system3 for separating white light emitted from the lamp unit 7 into light ofthree primary colors, and an image synthesizer 4 for irradiating theliquid crystal panels for three primary colors 43 b, 43 g, 43 r with thelight of three primary colors to generate image light of three primarycolors, and synthesizing the generated image light of three primarycolors into color image light.

The image synthesizer 4 includes a cube-like color synthesis prism 40having the liquid crystal panel for blue 43 b, liquid crystal panel forgreen 43 g and liquid crystal panel for red 43 r attached to threerespective side surfaces thereof. The three liquid crystal panels 43 b,43 g, 43 r have light incidence sides thereof provided with opticalcompensation sheet holders 6 b, 6 g, 6 r, respectively. The opticalcompensation sheet holders 6 b, 6 g, 6 r hold three optical compensationsheets (not shown) for blocking incidence of unwanted component waves oflight on the respective liquid crystal panels 43 b, 43 g, 43 r. Disposedbelow the image synthesizer 4 is, as shown in FIG. 4, a cooling system 8for cooling a plurality of optical components constituting the imagesynthesizer 4.

The liquid crystal projector device of the present invention will bedescribed below in detail in construction with reference to thedrawings.

Optical System 3

As shown in FIG. 5, the white light from the lamp unit 7 is guidedthrough a first integrator lens 31, the diaphragm mechanism 5, a secondintegrator lens 32, a slit plate 33, a polarization beam splitter 34 anda field lens 35 to a first dichroic mirror 36.

The first integrator lens 31 and second integrator lens 32 are made of aheat-resistant glass fly-eye lens as shown in FIG. 9, and have afunction of uniformizing illuminance distribution of the white lightemitted from the lamp unit 7. The slit plate 33 is made of an aluminumthin plate, and has a function of blocking unwanted incident lighttoward the polarization beam splitter 34. The polarization beam splitter34 has a function of extracting only one component wave out of P- andS-waves of light.

The light having passed through the polarization beam splitter 34 shownin FIG. 5 reaches through the field lens 35 to the first dichroic mirror36. The first dichroic mirror 36 has a function of reflecting only ablue component of light and passing red and green componentstherethrough. A second dichroic mirror 37 has a function of reflectingthe green component of light and passing the red component therethrough,and a field mirror 38 a has a function of reflecting the red component.Thus, the white light emitted from the lamp unit 7 is separated by thefirst and second dichroic mirrors 36, 37 into blue light, green lightand red light, and guided to the image synthesizer 4.

Image Synthesizer 4

As shown in FIG. 5, the image synthesizer 4 includes the cube-like colorsynthesis prism 40 having the liquid crystal panel for blue 43 b, liquidcrystal panel for green 43 g and liquid crystal panel for red 43 rattached to the three respective side surfaces thereof.

As shown in FIG. 3, the optical compensation sheet holders 6 b, 6 g, 6 rare attached to the light incidence sides of the three liquid crystalpanels 43 b, 43 g, 43 r, respectively. The optical compensation sheetholders 6 b, 6 g, 6 r hold the three optical compensation sheets 42 b,42 g, 42 r for blocking incidence of unwanted component waves of lighton the respective liquid crystal panels 43 b, 43 g, 43 r.

The blue light reflected by the first dichroic mirror 36 and a fieldmirror 38 c shown in FIG. 5 is guided by an incidence polarizing platefor blue 41 b through the incidence polarizing plate for blue 41 b, theoptical compensation sheet for blue 42 b, the liquid crystal panel forblue 43 b and an emergence polarizing plate for blue 44 b to the colorsynthesis prism 40.

The green light reflected by the second dichroic mirror 37 is guided byan incidence polarizing plate for green 41 g through the incidencepolarizing plate for green 41 g, the optical compensation sheet forgreen 42 g, the liquid crystal panel for green 43 g and an emergencepolarizing plate for green 44 g to the color synthesis prism 40.

Similarly, the red light transmitted by the first dichroic mirror 36 andsecond dichroic mirror 37 and reflected by two field mirrors 38 a, 38 bis guided by an incidence polarizing plate for red 41 r of the imagesynthesizer 4 through the incidence polarizing plate for red 41 r, theoptical compensation sheet for red 42 r, the liquid crystal panel forred 43 r and an emergence polarizing plate for red 44 r to the colorsynthesis prism 40.

The image light of the three colors guided to the color synthesis prism40 is synthesized by the color synthesis prism 40, and the resultingcolor image light is to be magnifyingly projected through the projectionlens 20 on a forward screen.

Diaphragm Mechanism 5

As shown in FIG. 5, the diaphragm mechanism 5 is arranged between thefirst integrator lens 31 and second integrator lens 32 constituting theoptical system 3. As shown in FIG. 3, the diaphragm mechanism 5 isattached to the optical system holding case 30, while inserted in theslit opening 320 provided at the left end of the optical system holdingcase 30.

The diaphragm system 5 is for regulating the amount of light to beincident on the liquid crystal panels for the respective colors 43 b, 43g, 43 r depending on input data for an image to be projected to therebyimprove a contrast of the projection image. For example, when input datafor an image to be projected concentrates in a low brightness region,that is, when the image to be projected is a generally dark image, thediaphragm mechanism 5 partly blocks the light emitted from the lamp unit7 to set a smaller than usually amount of light to be incident on theliquid crystal panels for the respective colors 43 b, 43 g, 43 r, whilea correction is made to the input data to expand a dynamic range. Thiscan improve a contrast of the projection image.

Of the light having passed through the second integrator lens 32 toreach the liquid crystal panels for the respective colors 43 b, 43 g, 43r, light having peripherally passed through the second integrator lens32 often causes light leak because it would be incident slantinglyrelative to a surface of each of the liquid crystal panels 43 b, 43 g,43 r compared with light having centrally passed through the secondintegrator lens 32. Accordingly, the diaphragm mechanism 5 blocks lightto be peripherally incident on the second integrator lens 32 to therebyprevent light leak from occurring in the liquid crystal panels for therespective colors 43 b, 43 g, 43 r, which improves a contrast of theprojection image.

As shown in FIG. 6 and FIG. 7, the diaphragm mechanism 5 includes aT-shaped first diaphragm plate 53 and an L-shaped second diaphragm plate54 superposed on each other on a plane perpendicular to the optical axisof light passing through the diaphragm mechanism 5, which are disposedinside a flat casing 50 formed by joining a rectangular base plate 51and a cover plate 52 to each other. Attached to the cover plate 52 is amotor 55 for driving the first diaphragm plate 53 and second diaphragmplate 54 toward or away from each other along the plane.

The base plate 51 and cover plate 52 have rectangular openings 51 a, 52a, respectively, formed therein. The light having passed through thefirst integrator lens 31 shown in FIG. 5 irradiates the secondintegrator lens 32 through the both openings 51 a, 52 a.

As shown in FIG. 6, the motor 55 has a turning member 56 attached to anoutput shaft thereof, which rotates together with the output shaft. Theturning member 56 has opposite ends thereof formed with projections 56a, 56 a toward the cover plate 52. The projections 56 a, 56 a areengaged with a pair of circular arc grooves 51 b, 51 b, 52 b, 52 bprovided in the base plate 51 and cover plate 52, respectively, shown inFIG. 7. As shown in FIG. 7, the first diaphragm plate 53 and seconddiaphragm plate 54 have left ends thereof provided with rectangularthrough holes 53 a, 54 a. The projections 56 a, 56 a of the turningmember 56 are through both through holes 53 a, 54 a, respectively.

The first diaphragm plate 53 and second diaphragm plate 54 have an upperend thereof and a lower end thereof provided with two guide holes 53 b,53 b, 54 b, 54 b, respectively, along a pair of long sides constitutinga rectangular contour of the diaphragm mechanism 5 shown in FIG. 6,while the base plate 51 has, along each of the pair of long sides, twoguide pins 51 c, 51 c, 51 d, 51 d, four in total, protruded from aninner surface thereof toward the cover plate 52. The two upper guidepins 51 c, 51 c are engaged with the two guide holes 53 b, 53 b of thefirst diaphragm plate 53, respectively. The two lower guide pins 51 d,51 d are engaged with the two guide holes 54 b, 54 b of the seconddiaphragm plate 54, respectively.

As shown in FIG. 9, the second integrator lens 32 includes 56rectangular cells 32 a arranged in the form of a matrix. The firstintegrator lens 31 also has the same arrangement as of the secondintegrator lens 32. As shown in FIGS. 10( a)-(c), the second integratorlens 32 is arranged such that optical centers of the cells 32 aconstituting the second integrator lens 32 correspond to focuses ofrespective cells 31 a constituting the first integrator lens 31.

Therefore, as shown in FIGS. 10( a)-(c), the cells 31 a of the firstintegrator lens 31 emit quadrangular-pyramid-shaped luminous fluxes 300toward the optical centers of the corresponding cells 32 a of the secondintegrator lens 32. Each of the luminous fluxes 300 has a rectangularcross-sectional shape at the set position of the diaphragm mechanism 5.

As shown in FIG. 7, the first diaphragm plate 53 and second diaphragmplate 54 have recesses 53 c, 54 c, respectively, formed on opposed endfaces thereof. Both recesses 53 c, 54 c are each formed in the shape ofstairs along latticed border lines between a plurality of luminousfluxes 300 from respective cells 31 a of the first integrator lens 31 torespective cells 32 a of the second integrator lens 32.

As shown in FIGS. 8( a)-(e), the recesses 53 c, 54 c of both diaphragmplates 53, 54 are exposed from the openings 51 a, 52 a in accordancewith slide operation of both diaphragm plates 53, 54. The light havingpassed through the first integrator lens 31 reaches the secondintegrator lens 32 through a light passage window 57 surrounded by bothrecesses 53 c, 54 c.

FIGS. 8( a)-(e) show states where the recesses 53 c, 54 c of bothdiaphragm plates 53, 54 have end faces thereof positioned on latticedborder lines between a plurality of luminous fluxes 300 from respectivecells 31 a of the first integrator lens 31 to respective cells 32 a ofthe second integrator lens 32 (hereafter referred to as ideal lightblocking states).

FIGS. 9( a)-(e) show areas of light irradiated on the second integratorlens 32 with hatching when the diaphragm mechanism 5 is set in the ideallight blocking states shown in FIGS. 8( a)-(e). FIGS. 10( a)-(c) showthat when the diaphragm mechanism 5 is set as shown in FIG. 8( a), FIG.8( c) and FIG. 8( e), respectively, the diaphragm mechanism 5 blocks aplurality of luminous fluxes 300 of all the luminous fluxes 300 from therespective cells 31 a of the first integrator lens 31 to the respectivecells 32 a of the second integrator lens 32.

As shown in FIGS. 8( a)-(e), when the motor 55 rotates clockwise, thefirst diaphragm plate 53 slides rightward, while the second diaphragmplate 54 slides leftward. Consequently, the first diaphragm plate 53 andsecond diaphragm plate 54 are moved toward each other. This makes largerthe area of the first diaphragm plate 53 and second diaphragm plate 54exposed from the openings 51 a, 52 a.

On the other hand, when the motor 55 rotates counterclockwise, the firstdiaphragm plate 53 slides leftward, while the second diaphragm plate 54slides rightward. Consequently, the first diaphragm plate 53 and seconddiaphragm plate 54 are moved away from each other. This makes smallerthe area of the first diaphragm plate 53 and second diaphragm plate 54exposed from the openings 51 a, 52 a.

As described above, because the area of the first diaphragm plate 53 andthe second diaphragm plate 54 exposed from the openings 51 a, 52 avaries depending on the rotation angle of the motor 55, the lightirradiation region on the second integrator lens 32 can be varied bycontrolling the rotation angle of the motor 55 between the first ideallight blocking state shown in FIG. 8( a) and the fifth ideal lightblocking state shown in FIG. 8( e).

In the first ideal light blocking state shown in FIG. 8( a), the turningmember 56 is turned counterclockwise by the motor 55 to the limitposition. In this state, as shown in FIG. 9( a) and FIG. 10( a), all the56 cells 32 a constituting the second integrator lens 32 are irradiatedwith light. On the other hand, in the fifth ideal light blocking stateshown in FIG. 8( e), the turning member 56 is turned clockwise by themotor 55 to the limit position. In this state, as shown in FIG. 9( e)and FIG. 10( c), only four central constituent cells 32 a of the secondintegrator lens 32 are irradiated with light. In the second ideal lightblocking state shown in FIG. 8( b), as shown in FIG. 9( b), 44 cells 32a except 12 cells 32 a arranged peripherally in the second integratorlens 32 are irradiated with light.

Similarly, in the third ideal light blocking state shown in FIG. 8( c),as shown in FIG. 9( c) and FIG. 10( b), only 28 cells 32 a generally inthe form of a cross arranged centrally of the second integrator lens 32are irradiated with light. In the fourth ideal light blocking stateshown in FIG. 8( d), as shown in FIG. 9( d), only 12 cells 32 agenerally in the form of a cross arranged centrally of the secondintegrator lens 32 are irradiated with light.

If the diaphragm mechanism 5 is set in an intermediate state between thefirst to fifth ideal light blocking states shown in FIGS. 8( a)-(e),that is, if the first diaphragm plate 53 and second diaphragm plate 54move so as to partly block passage of at least one luminous flux 300 ofall the luminous fluxes 300 from the respective cells 31 a of the firstintegrator lens 31 to the respective cells 32 a of the second integratorlens 32, and to allow passage thereof in the other part, then unevencoloring can occur in the projection image.

Because the opposed recesses 53 c, 54 c of both diaphragm plates 53, 54defining the light passage window 57 that allows passage of light areformed in the shape of stairs along latticed border lines between aplurality of luminous fluxes 300 from respective cells 31 a of the firstintegrator lens 31 toward respective cells 32 a of the second integratorlens 32, the diaphragm mechanism 5 of the present invention changes fromthe intermediate state to any one of the first to fifth ideal lightblocking states whenever the end faces of the recesses 53 c, 54 c ofboth diaphragm plates 53, 54 reach the latticed border lines duringreciprocation of both diaphragm plates 53, 54. Therefore, both diaphragmplates 53, 54 are set in the ideal light blocking state more frequentlythan conventionally during reciprocation of both diaphragm plates 53,54. Consequently, occurrence of uneven coloring is suppressed more thanconventionally.

In addition, because the recesses 53 c, 54 c of both diaphragm plates53, 54 are formed in the shape of stairs along latticed border linesbetween a plurality of luminous fluxes 300 from respective cells 31 a ofthe first integrator lens 31 to respective cells 32 a of the secondintegrator lens 32, the diaphragm mechanism 5 can be constituted of aone-directional slide mechanism for horizontally moving both diaphragmplates 53, 54 close or away. This allows the more simplified diaphragmmechanism 5 than a conventional one that needs a two-directional slidemechanism.

Optical Compensation Sheet Holders 6 b, 6 g, 6 r

As shown in FIG. 3, the optical compensation sheet holders 6 b, 6 g, 6 rare attached to the optical system holding case 30 at three end edgesthereof opposed to three side surfaces of the color synthesis prism 40of the image synthesizer 4. The optical compensation sheet holders 6 b,6 g, 6 r hold the optical compensation sheets 42 b, 42 g, 42 r,respectively, shown in FIG. 5. As shown in FIG. 5, the opticalcompensation sheets 42 b, 42 g, 42 r are arranged between the incidencepolarizing plates for the respective colors 41 b, 41 g, 4lr and theliquid crystal panels for the respective colors 43 b, 43 g, 43 r,respectively.

The optical compensation sheets 42 b, 42 g, 42 r have liquid crystalmolecules therein. The optical compensation sheets 42 b, 42 g, 42 r areattached such that the liquid crystal molecules have a slow axis in adirection parallel to an alignment direction of liquid crystal moleculesconstituting the respective liquid crystal panels 43 b, 43 g, 43 r tothereby perform a function of blocking incidence of unwanted componentwaves of light on the respective liquid crystal panels 43 b, 43 g, 43 r.This can prevent light leak and uneven coloring from occurring in theliquid crystal panels 43 b, 43 g, 43 r.

Because the three optical compensation sheet holders 6 b, 6 g, 6 r havethe same configuration, only the optical compensation sheet holder forblue 6 b will be described below, and the optical compensation sheetholders for green and red 6 g, 6 r will not be described. As shown inFIG. 11, the optical compensation sheet 42 b is held by the opticalcompensation sheet holder 6 b turnably within a plane perpendicular toan optical axis of light (indicated by the dashed line in the drawing)passing through the optical compensation sheet 42 b, and turnably on arotation axis parallel to a plane perpendicular to the optical axis. Theattachment posture of the optical compensation sheet 42 b can beadjusted by adjusting fastening positions of two screws 64 a, 64 b, asdescried later. The attachment posture of each of the opticalcompensation sheets 42 b, 42 g, 42 r is adjusted in an adjustmentprocess before shipment of the liquid crystal projector device.

As shown in FIG. 11 and FIG. 12, the optical compensation sheet holder 6b includes a rectangular frame 61 for holding the optical compensationsheet 42 b, a turning member 62 for turnably holding the frame 61 and tobe attached to the optical system holding case 30, and a slide member 63to engage with the frame 61.

As shown in FIG. 12, the frame 61 has a pair of columnar shanks 61 a, 61a protruded therefrom so as to be approximately parallel to one of twodiagonals of the liquid crystal panel for blue 43 b, and a steppedprojection 61 b protruded upward from the upper left corner of the frame61. The optical compensation sheet 42 b is fitted in an opening 61 cprovided centrally of the frame 61.

The turning member 62 has a rectangular holding part 62 a for holdingthe frame 61, and an attachment part 62 b along an upper wall 310 of theoptical system holding case 30. The holding part 62 a has a rectangularopening 62 c provided centrally therein, and a pair of supports 66 a, 66b for supporting the shanks 61 a, 61 a of the frame 61, protruded aroundthe opening 62 c, on a line approximately parallel to one of twodiagonals of the liquid crystal panel for blue 43 b, and in thetraveling direction of light passing through the optical compensationsheet 42 b. Of the pair of supports 66 a, 66 b, one support 66 a isformed with a through hole through which the shank 61 a of the frame 61penetrates, while the other support 66 b is L-shaped. The holding part62 a has a pair of flat springs 67 a, 67 b formed downward from loweropposite ends thereof, while the holding part 62 a has a semicircularrecess 65 formed at the lower left end thereof.

The optical system holding case 30 has a side wall 311 having a pair offoot parts 314 a, 314 b protruded therefrom in the optical axisdirection of light to pass through the optical compensation sheet 42 b.Both foot parts 314 a, 314 b are formed with grooves 315 a, 315 b intowhich both flat springs 67 a, 67 b of the holding part 62 a are to beinserted. The flat springs 67 a, 67 b are to be held between opposedsurfaces of the grooves 315 a, 315 b, respectively, with the opticalcompensation sheet holder 6 b attached to the optical system holdingcase 30. Further, the left groove 315 a has a columnar shank 316 formedtherein parallel to the optical axis. The recess 65 of the holding part62 a is to be fitted with the shank 316.

The attachment part 62 b of the turning member 62 is provided with ascrew hole 68 through which a screw 64 a for fixing the slide member 63penetrates, a first long hole 69 a through which a screw 64 b for fixingthe turning member 62 to the upper wall 310 of the optical systemholding case 30 penetrates, and a third long hole 69 b through which apair of pins 312 a, 312 b protruded from the upper wall 310 of theoptical system holding case 30 penetrate. The pair of pins 312 a, 312 bare provided away from each other in the right-and-left directionperpendicular to the optical axis of light to pass through the opticalcompensation sheet 42 b. The first long hole 69 a and third long hole 69b are shaped to be long in the left-and-right direction.

The slide member 63 has a flat plate part 63 a along the attachment part62 b of the turning member 62, and a U-shaped pinching part 63 bprotruded downward from one corner of the flat plate part 63 a. The flatplate part 63 a is provided with a second long hole 69 c longer in theoptical axis direction of light to pass through the optical compensationsheet 42 b. The screw 64 a for fixing the slide member 63 to theattachment part 62 b of the turning member 62 is to penetrate throughthe second long hole 69 c. The pinching part 63 b is to pinch theprojection 61 b of the frame 61.

The optical compensation sheet holder 6 b is adjusted in place using afirst adjustment operation of turning the optical compensation sheetholder 6 b, with the screw 64 b loosened, on the shank 316 provided onthe left foot part 314 a of the optical system holding case 30 within aplane perpendicular to the optical axis of light to pass through theoptical compensation sheet 42 b, and a second adjustment operation ofsliding the slide member 63 of the optical compensation sheet holder 6b, with the screw 64 a loosened, along the optical axis direction tothereby turn the frame 61 on the pair of shanks 61 a, 61 a, so that asurface of the optical compensation sheet 42 b is inclined relative to aplane perpendicular to the optical axis.

FIGS. 13( a)-(c) show the optical compensation sheet holder 6 b, theattachment posture of which is adjusted by the first adjustmentoperation.

As shown in FIG. 11, the pair of pins 312 a, 312 b of the optical systemholding case 30 are through the third long hole 69 b of the turningmember 62 of the optical compensation sheet holder 6 b. Therefore,loosening the screw 64 b allows slide operation of the opticalcompensation sheet holder 6 b within the first long hole 69 a in theleft-and-right direction perpendicular to the optical axis of light topass through the optical compensation sheet 42 b.

The recess 65 of the turning member 62 of the optical compensation sheetholder 6 b is engaged with the shank 316 provided on the left foot part314 a of the optical system holding case 30. Therefore, as shown inFIGS. 13( a)-(c), the slide operation of the optical compensation sheetholder 6 b in the left-and-right direction causes the opticalcompensation sheet holder 6 b to turn about the shank 316 within a planeperpendicular to the optical axis.

FIG. 13( a) shows a state where the screw 64 b is fastened at the rightend of the first long hole 69 a of the optical compensation sheet holder6 b (hereafter referred to as the first fastened state). FIG. 13( c)shows a state where the screw 64 b is fastened at the left end of thefirst long hole 69 a of the optical compensation sheet holder 6 b(hereafter referred to as the second fastened state). FIG. 13( b) showsa state where the screw 64 b is fastened at the center of the first longhole 69 a of the optical compensation sheet holder 6 b (hereafterreferred to as the third fastened state).

According. to the first adjustment operation, as shown in FIGS. 13(a)-(c), the attachment posture of the optical compensation sheet holder6 b can be adjusted between the first fastened state and second fastenedstate.

FIGS. 14( a)-(c) show the optical compensation sheet holder 6 b, theattachment posture of which is adjusted by the second adjustmentoperation.

As shown in FIG. 11, the slide member 63 of the optical compensationsheet holder 6 b is fastened to the turning member 62 by the screw 64 athrough the second long hole 69 c of the slide member 63. Loosening thescrew 64 a allows slide operation of the slide member 63 along theoptical axis within the second long hole 69 c.

Because the projection 61 b of the frame 61 is pinched by the pinchingpart 63 b of the slide member 63, the projection 61 b of the frame 61moves along the optical axis together with the slide member 63. Thiscauses the frame 61 to turn on the pair of shanks 61 a, 61 a formedalong one diagonal of the optical compensation sheet 42 b, so that asurface of the optical compensation sheet 42 b fixed to the frame 61 isinclined relative to a plane perpendicular to the optical axis.

FIG. 14( a) shows a state where the screw 64 a is fastened at the frontend of the second long hole 69 c of the slide member 63 (hereafterreferred to as the fourth fastened state). In the fourth fastened state,the upper left end of the frame 61 having the projection 61 b protrudedtherefrom projects forward along the optical axis more than the lowerright end of the frame 61.

On the other hand, FIG. 14( c) shows a state where the screw 64 a isfastened at the rear end of the second long hole 69 c (hereafterreferred to as the fifth fastened state). In the fifth fastened state,the upper left end of the frame 61 retreats along the optical axisbackward more than the lower right end of the frame 61.

FIG. 14( b) shows a state where the screw 64 a is fastened at the centerof the second long hole 69 c (hereafter referred to as the sixthfastened state). In the sixth fastened state, the optical compensationsheet 42 b fixed to the frame 61 has a surface approximatelyperpendicular to the optical axis.

According to the second adjustment operation, as shown in FIGS. 14(a)-(c), the attachment posture of the optical compensation sheet holder6 b can be adjusted between the fourth fastened state and fifth fastenedstate.

The attachment posture of the optical compensation sheet holder 6 b isadjusted before shipment of the liquid crystal projector device.Specifically, the attachment posture of the optical compensation sheetholder 6 b is adjusted by projecting an adjustment image using theliquid crystal projector device and using the first and secondadjustment operations to ensure that the adjustment image has a clearblack-and-white contrast.

According to the first adjustment operation, the optical compensationsheet 42 b can be adjusted in its attachment posture turnably within aplane perpendicular to the optical axis. Therefore, the slow axis of theliquid crystal molecules in the optical compensation sheet 42 b viewedfrom the optical axis direction can be set approximately parallel to analignment direction of liquid crystal molecules of the liquid crystalpanel 43 b shown in FIG. 5.

According to the second adjustment operation, the inclination angle ofthe surface of the optical compensation sheet 42 b relative to a planeperpendicular to the optical axis is adjustable. Therefore, the apparentslow axis of the optical compensation sheet 42 b can correspond to theslow axis in the optical axis direction of the liquid crystal moleculesin the liquid crystal panel 43 b shown in FIG. 5.

Further, the above second adjustment operation can incline the surfaceof the optical compensation sheet 42 b relative to the optical axis onthe rotation axis approximately parallel to one diagonal of the liquidcrystal panel 43 b. That is, because the surface of the opticalcompensation sheet 42 b can be inclined relative to one diagonal of theliquid crystal panel 43 b, the attachment posture of the opticalcompensation sheet holder 6 b is adjusted more easily thanconventionally.

Furthermore, as shown in FIG. 11, the optical compensation sheet 42 b isfixed to the frame 61, and the frame 61 is supported by the turningmember 62 turnably on the rotation axis. Therefore, the frame 61 andoptical compensation sheet 42 b will not experience any unnatural forcein adjustment with the second adjustment operation. This can preventwarpages and flexures from occurring in the frame 61 and opticalcompensation sheet 42 b, and, as a result, provide a uniform projectionimage with a clearer contrast than a conventional one, and withoutuneven coloring or the like.

Lens Shift Mechanism 2

As shown in FIG. 2, the projection lens system includes the projectionlens 20 and cylinder 21 for holding the projection lens. The projectionlens system is held by the lens shift mechanism 2, and attached to theforward end of the optical system holding case 30. The lens shiftmechanism 2 is for horizontally and vertically reciprocatingly movingthe projection lens system within a certain range where the brightnessof color image light will not be significantly reduced.

The projector device with the lens shift mechanism 2 makes it easierthan ever to adjust an image display position relative to a screenbecause the lens shift mechanism 2 makes it possible to adjust the imagedisplay position relative to the screen after appropriately positioningthe projector device relative to the screen.

As shown in FIG. 15 and FIG. 16, the lens shift mechanism 2 includes astationary base 120, a movable member 125 to which the projection lenssystem is attached, a vertical drive mechanism 23 for vertically drivingthe movable member 125, and a horizontal drive mechanism 22 forhorizontally driving the movable member 125.

As shown in FIG. 17 and FIG. 19, the stationary base 120 includes ametal front plate 122 screwed on the front of a metal back case 121. Theback case 121 and front plate 122 have circular openings 121 a, 122 b,respectively, formed centrally therein. The cylinder 21 is to beinserted into both openings 121 a, 122 b.

The movable member 125 includes a vertically movable plate 123 and ahorizontally movable plate 124 in close contact with each other, and isplaced inside the stationary base 120. The vertically movable plate 123and horizontally movable plate 124 are generally rectangular. Bothmovable plates 123, 124 have circular openings 123 c, 124 c,respectively, formed centrally therein, into which the cylinder 21 is tobe inserted.

As shown in FIG. 17, the cylinder 21 has an outer peripheral surfacethereof formed with a rectangular flange 21 a. The cylinder 21 is to beattached to the movable member 125 with the flange 21 a held between thehorizontally movable plate 124 and vertically movable plate 123.

As shown in FIG. 19, the vertically movable plate 123 has four verticalguide pins 123 a, 123 a, 123 b, 123 b protruded from a front surfacethereof toward the horizontally movable plate 124. The horizontallymovable plate 124 is provided with two vertically long slot-like guideholes 124 b, 124 b. The two lower vertical guide pins 123 a, 123 a ofthe vertically movable plate 123 are to penetrate through the respectiveguide holes 124 b, 124 b. The horizontally movable plate 124 has a backsurface thereof provided with two vertically long slot-like guidegrooves 124 d, 124 d. The two upper vertical guide pins 123 b, 123 b ofthe vertically movable plate 123 are to engage with the respective guidegrooves 124 d, 124 d.

The horizontally movable plate 124 has a right end thereof formed with ahorizontally extending rack 126. The rack 126 is to engage with a laststage pinion 27 b constituting the horizontal drive mechanism 22 shownin FIG. 18. As shown in FIG. 19, the horizontally movable plate 124 hastwo horizontal guide pins 124 a, 124 a protruded from upper oppositeends of a front surface thereof toward the front plate 122, while thefront plate 122 has two horizontally long slot-like guide holes 122 a,122 a provided therein. The two horizontal guide pins 124 a, 124 a ofthe horizontally movable plate 124 are to penetrate through both guideholes 122 a, 122 a, respectively.

As shown in FIG. 17 and FIG. 18, the horizontal drive mechanism 22includes a horizontal operation dial 24 to be operated by a user, and aplurality of transmission gears 24 a, 25, 26, 27 for converting rotarymotion of the horizontal operation dial 24 to linear motion of thehorizontally movable plate 124. As shown in FIG. 1, the horizontaloperation dial 24 is partly exposed from the right side wall of thecasing 1.

As shown in FIG. 18, the horizontal operation dial 24 is disposedrotatably on a vertical rotation axis. The spur gear 24 a is provided onthe reverse surface of the horizontal operation dial 24. The spur gear24 a is engaged with a spur gear 25 a of the first transmission gear 25,which rotates on a vertical rotation axis. The spur gear 25 a is engagedwith a spur gear 26 a of the second transmission gear 26, which rotateson a vertical rotation axis. The second transmission gear 26 has a worm26 b engaged with a worm wheel 27 a formed at one end of the thirdtransmission gear 27, which rotates on a rotation axis along the opticalaxis of the projection lens system. The rack 126 of the horizontallymovable plate 124 is engaged with the pinion 27 b of the thirdtransmission gear 27.

The vertical drive mechanism 23 includes a vertical operation dial 28 tobe operated by a user, a plurality of transmission gears 28 a, 29, 130,131 for converting rotary motion of the vertical operation dial 28 tolinear motion of the vertically movable plate 124, a turning plate 127and a connection plate 128. As shown in FIG. 1, the vertical operationdial 28 is partly exposed from the right side wall of the casing 1.

The vertical operation dial 28 is disposed rotatably on a rotation axisalong the optical axis. The spur gear 28 a is provided on the reversesurface of the vertical operation dial 28. The spur gear 28 a is engagedwith a spur gear 29 a at one end of the fourth transmission gear 29,which rotates on a rotation axis along the optical axis. The fourthtransmission gear 29 has a face gear 29 b at the other end thereofengaged with a bevel gear 130 a formed at one end of the fifthtransmission gear 130. The fifth transmission gear 130 has a worm 130 bengaged with a worm wheel 131 a at one end of the sixth transmissiongear 131, which rotates on a rotation axis along the optical axis. Thesixth transmission gear 131 has a spur gear 131 b at the other endthereof engaged with a sector gear portion 127 a of the turning plate127 shown in FIG. 17 and FIG. 19.

As shown in FIG. 19, the turning plate 127 has an axial bore 127 bprovided centrally therein. The turning plate 127 is attached to thefront plate 122 of the stationary base 120 by a support pin 132 throughthe axial bore 127 b turnably on the support pin 132. The sector gearportion 127 a is formed at the right end of the turning plate 127, whilethe turning plate 127 has a left end thereof provided with a throughhole 127 c. The turning plate 127 is connected to the connection plate128 by a connection pin 129 through the through hole 127 c.

The connection plate 128 has both right and left ends thereof providedwith screw holes 128 a, 128 a, respectively. The connection plate 128 isfixed to the lower end of the vertically movable plate 123 with twoscrews through both screw holes 128 a, 128 a fastened to top ends of thetwo lower vertical guide pins 123 a, 123 a of the vertically movableplate 123 exposed from the opening 122 b of the front plate 122.

The connection plate 128 has a horizontally long slot-like engagementhole 128 b provided centrally therein. The connection pin 129 is throughthe engagement hole 128 b. Therefore, the connection plate 128 andturning plate 127 are to be connected to each other such that theconnection plate 128 can be horizontally displaced relative to theturning plate 127 within the engagement hole 128 b.

When a user rotates the horizontal operation dial 24 clockwise, thehorizontal operation dial 24 transmits its turning force via theplurality of transmission gears 24 a, 25, 26, 27 constituting the abovehorizontal drive mechanism 22 to the rack 126 of the horizontallymovable plate 124 shown in FIG. 15. The horizontal guide pins 124 a ofthe horizontally movable plate 124 are then guided by the respectivehorizontal guide holes 122 a of the front plate 122 a to slide thehorizontally movable plate 124 leftward.

The vertically movable plate 123 can be horizontally displaced relativeto the turning plate 127 within the engagement hole 128 b of theconnection plate 128. Further, the vertically movable plate 123 isrestrained from being horizontally displaced relative to thehorizontally movable plate 124 by engagement of the two lower verticalguide pins 123 a, 123 a of the vertically movable plate 123 with thevertical guide holes 124 b, 124 b of the horizontally movable plate 124,and engagement of the two upper vertical guide pins 123 b, 123 b shownin FIG. 19 with the vertical guide grooves 124 d, 124 d of thehorizontally movable plates 124. Therefore, the vertically movable plate123 and the projection lens system attached to the vertically movableplate 123 slide horizontally together with the horizontally movableplate 124 as shown in FIG. 15.

Similarly, when a user rotates the horizontal operation dial 24counterclockwise, the horizontally movable plate 124, vertically movableplate 123 and projection lens system slide rightward.

In FIG. 15, the dashed line shows the horizontally movable plate 124 andvertically movable plate 123 slid leftward to the limit position, andthe double-dashed line shows the horizontally movable plate 124 andvertically movable plate 123 slid rightward to the limit position. Thesolid line shows the horizontally movable plate 124 and verticallymovable plate 123 in the horizontally central position. The centralposition can provide the brightest projection image. As the horizontallymovable plate 124 and vertically movable plate 123 move leftward orrightward away from the central position, the brightness of theprojection image slightly lowers.

As shown in FIG. 15, when the horizontally movable plate 124 andvertically movable plate 123 are in the horizontally central position,the connection pin 129 is positioned on a vertically extending linethrough the centroid of the projection lens system.

When a user rotates the vertical operation dial 28 clockwise, thevertical operation dial 28 transmits its turning force via the pluralityof transmission gears 28 a, 29, 130, 131 constituting the vertical drivemechanism 23 shown in FIG. 18 to the sector gear portion 127 a of theturning plate 127 shown in FIG. 16. The turning plate 127 then turnscounterclockwise on the support pin 132, causing the left end of theturning plate 127 to move downward.

The turning plate 127 has the connection plate 128 connected to the leftend thereof via the connection pin 129. The connection plate 128 isfixed to the vertically movable plate 123. Therefore, as the turningplate 127 turns counterclockwise, the two lower vertical guide pins 123a, 123 a of the vertically movable plate 123 are guided by the verticalguide holes 124 b, 124 b of the horizontally movable plate 124, and thetwo upper vertical guide pins 123 b, 123 b shown in FIG. 19 are guidedby the vertical guide grooves 124 d, 124 d of the horizontally movableplate 124, to move the vertically movable plate 123 and the projectionlens system attached to the vertically movable plate 123 downwardrelative to the horizontally movable plate 124.

On the other hand, when a user rotates the vertical operation dial 28counterclockwise, the turning plate 127 turns clockwise on the supportpin 132, causing the left end of the turning plate 127 to move upward.This causes the vertically movable plate 123 and the projection lenssystem to be displaced upward relative to the horizontally movable plate124.

In FIG. 16, the dashed line shows the vertically movable plate 123 slidupward to the limit position, and the double-dashed line shows thevertically movable plate 123 slid downward to the limit position. Thesolid line shows the vertically movable plate 123 in the verticallycentral position. The central position can provide the brightestprojection image. As the vertically movable plate 123 moves upward ordownward away from the central position, the brightness of theprojection image slightly lowers.

The above lens shift mechanism 2 makes it possible to minimize theturning force to act on the vertically movable plate 123 due to theself-weight of the projection lens system in vertical shift operation ofthe projection lens system because the turning plate 127 constitutingthe vertical drive mechanism 23 and the vertically movable plate 123having the projection lens system attached thereto are connected to eachother by the connection pin 129 on a vertically extending line throughthe centroid of the projection lens system. This enables the projectionlens system to be vertically driven smoothly.

As shown in FIG. 20 and FIG. 21, the lens shift mechanism 2 includes alock mechanism 140 for fixing the projection lens system in a desiredposition. The lock mechanism 140 is for fixing the projection lenssystem in place after adjusting an image projected from the liquidcrystal projector device in place in accordance with a forward screenusing the lens shift mechanism 2 in setting of the liquid crystalprojector device. The lock mechanism 140 eliminates the necessity oflater readjustment unless the liquid crystal projector device or screenis moved.

As shown in FIG. 21, the lock mechanism 140 includes the lever member133 slidable along the optical axis of the projection lens system, ahorizontal lock member 137 to disengagably engage with the spur gear 24a of the horizontal operation dial 24, and a vertical lock member 136 todisengagably engage with the spur gear 28 a of the vertical operationdial 28, in accordance with slide operation of the lever member 133. Asshown in FIG. 20, the lever member 133 is attached to an attachmentplate 139 fastened to the stationary base 120, and slidable along theoptical axis between an unlocked position indicated by the solid lineand a locked position indicated by the double-dashed line in thedrawing. As shown in FIG. 1, the knob 134 of the lever member 133 isexposed from the right side wall of the casing 1.

In adjustment of the image projection position using the lens shiftmechanism 2, the lever member 133 is set in the unlocked position. Aftercompletion of the adjustment, the knob 134 of the lever member 133 isoperated to slide the lever member 133 to the locked position, wherebythe horizontal lock member 137 and vertical lock member 136 shown inFIG. 21 are engaged with the spur gears 24 a, 28 a of the horizontaloperation dial 24 and vertical operation dial 28 constituting the lensshift mechanism 2, to disable both operation dials 24, 28 from rotating.This enables the projection lens system to be fixed in a desiredposition.

If the image projection position needs readjustment, the knob 134 of thelever member 133 is operated to slide the lever member 133 to theunlocked position, whereby the horizontal lock member 137 and verticallock member 136 shown in FIG. 21 are disengaged from the spur gears 24a, 28 a of the horizontal operation dial 24 and vertical operation dial28 constituting the lens shift mechanism 2, to enable both operationdials 24, 28 to rotate.

FIG. 22( a) and FIG. 22( b) show a relative position relationshipbetween the lever member 133 and vertical lock member 136, with thelever member 133 set in the locked position or unlocked position. Asshown in FIG. 22( a) and FIG. 22( b), the vertical lock member 136 isapproximately L-shaped, and attached to the attachment plate 139 shownin FIG. 20 turnably on a rotation axis 136 b along the optical axis. Thevertical lock member 136 has one end thereof formed with a gear portion136 a.

The rotation axis 136 b of the vertical lock member 136 has a torsionspring 141 fitted therearound. The torsion spring 141 has one endthereof locked on the attachment plate 139, and the other end hung onthe back surface of the gear portion 136 a of the vertical lock member136.

The elastic restoring force of the torsion spring 141 causescounterclockwise turning force to act on the vertical lock member 136.The gear portion 136 a of the vertical lock member 136 is always biasedby the turning force toward the spur gear 28 a of the vertical operationdial 28.

When the lever member 133 is set in the locked position, the levermember 133 is positioned rearward along the optical axis, as indicatedby the double-dashed line in FIG. 20. In this state, the lever member133 has an end 133 a thereof spaced apart from the vertical lock member136 as shown in FIG. 22( a). The gear portion 136 a of the vertical lockmember 136 is engaged with the spur gear 28 a of the vertical operationdial 28 by the biasing force of the torsion spring 141. This results inthe vertical operation dial 28 disabled from rotating.

On the other hand, when the lever member 133 is set in the unlockedposition, the lever member 133 is positioned forward along the opticalaxis, as indicated by the solid line in FIG. 20. In this state, the end133 a of the lever member 133 touches one end of the vertical lockmember 136 as shown in FIG. 22( b). This causes the vertical lock member136 to turn counterclockwise against the biasing force of the torsionspring 141.

Consequently, the gear portion 136 a formed at the other end of thevertical lock member 136 moves away from the spur gear 28 a of thevertical operation dial 28. This results in the vertical operation dial28 enabled to rotate.

FIG. 23( a) and FIG. 23( b) show a relative position relationshipbetween the lever member 133 and horizontal lock member 137, with thelever member 133 set in the locked position or unlocked position. Asshown in FIG. 23( a) and FIG. 23( b), the horizontal lock member 137 isapproximately L-shaped, and attached to the attachment plate 139 shownin FIG. 20 turnably on a vertical rotation axis 137 b. The horizontallock member 137 has one end thereof formed with a gear portion 137 a.

The rotation axis 137 b of the horizontal lock member 137 has a torsionspring 141 fitted therearound. The torsion spring 141 has one endthereof locked on the attachment plate 139, and the other end hung onthe back surface of the gear portion 137 a of the horizontal lock member137.

The elastic restoring force of the torsion spring 141 causescounterclockwise turning force to act on the horizontal lock member 137.The gear portion 137 a of the horizontal lock member 137 is alwaysbiased by the turning force toward the spur gear 24 a of the horizontaloperation dial 24.

When the lever member 133 is set in the locked position, the levermember 133 is positioned rearward along the optical axis, as indicatedby the double-dashed line in FIG. 20. In this state, the lever member133 has an end 133 b thereof spaced apart from the horizontal lockmember 137 as shown in FIG. 23( a). The gear portion 137 a of thehorizontal lock member 137 is engaged with the spur gear 24 a of thehorizontal operation dial 24 by the biasing force of the torsion spring141. This results in the horizontal operation dial 24 disabled fromrotating.

On the other hand, when the lever member 133 is set in the unlockedposition, the lever member 133 is positioned forward along the opticalaxis, as indicated by the solid line in FIG. 20. In this state, the end133 b of the lever member 133 touches one end of the horizontal lockmember 137 as shown in FIG. 23( b). This causes the horizontal lockmember 137 to turn clockwise against the biasing force of the torsionspring 141.

Consequently, the gear portion 137 a formed at the other end of thehorizontal lock member 137 moves away from the spur gear 24 a of thehorizontal operation dial 24. This results in the horizontal operationdial 24 enabled to rotate.

Therefore, the liquid crystal projector device of the present inventioncan realize, with a simple structure, the lock mechanism 140 capable ofsimultaneously setting the two operation dials 24, 28 so as to rotate ornot to rotate, with slide operation of the single lever member 133.

The lens shift mechanism 2 further includes a first click-feelinggeneration mechanism 150 for giving a certain click-feeling to thehorizontal operation dial 24 when operation of the horizontal operationdial 24 brings the projection lens system into the horizontally centralposition indicated by the solid line in FIG. 15, and a secondclick-feeling generation mechanism 151 for giving a certainclick-feeling to the operation of the vertical operation dial 28 whenoperation of the vertical operation dial 28 brings the projection lenssystem into the vertically central position indicated by the solid linein FIG. 16.

As shown in FIG. 24( a) and FIG. 24( b), the first click-feelinggeneration mechanism 150 includes a first whorl groove 150 a provided ina side surface of the first transmission gear 25 constituting thehorizontal drive mechanism 22, a first turning member 135 to slide onthe first whorl groove 150 a along with rotation of the firsttransmission gear 25, and a torsion spring 153 fitted around a rotationaxis 135 a of the first turning member 135. The first turning member 135is attached to the attachment plate 139 shown in FIG. 20 turnably on thevertical rotation axis 135 a provided at one end of the first turningmember 135.

The first turning member 135 has the other end thereof formed with aprojection 135 b projecting toward the first transmission gear 25. Theprojection 135 b is engaged with the first whorl groove 150 a. The firstturning member 135 has a clockwise turning force on the rotation axis135 a caused by the elastic restoring force of the torsion spring 153,whereby the projection 135 b is biased toward the inner peripheral wallsurface of the first whorl groove 150 a.

Therefore, when a user rotates the horizontal operation dial 24 tothereby rotate the first transmission gear 25, the projection 135 b ofthe first turning member 135 slides on the first whorl groove 150 awhile contacting the inner peripheral wall surface of the first whorlgroove 150 a.

When the rotation of the horizontal operation dial 24 brings theprojection lens system into the horizontally central position indicatedby the solid line in FIG. 15, the projection 135 b of the first turningmember 135 is engaged by the biasing force of the torsion spring 153with a recess 150 b provided on the inner peripheral wall surface of thefirst whorl groove 150 a, as shown in FIG. 24( b).

The certain click-feeling will be given to the operation of thehorizontal operation dial 24 by a collision made when the projection 135b of the first turning member 135 engages with the recess 150 b of thefirst whorl groove 150 a. In order to further rotate the horizontaloperation dial 24 from this state, it is necessary to disengage theprojection 135 b of the first turning member 135 from the recess 150 bof the first whorl groove 150 a against the biasing force of the torsionspring 153. This will give a certain resistance force to the rotationoperation of the horizontal operation dial 24.

As shown in FIG. 25( a) and FIG. 25( b), the second click-feelinggeneration mechanism 151 includes a second whorl groove 151 a providedin a side surface of the fourth transmission gear 29 constituting thevertical drive mechanism 23, a second turning member 138 to slide on thesecond whorl groove 151 a along with rotation of the fourth transmissiongear 29, and a coil spring 155 for giving a clockwise turning force tothe second turning member 138.

The second turning member 138 is approximately L-shaped, and attached tothe attachment plate 139 shown in FIG. 15 and FIG. 16 turnably on therotation axis 138 a extending along the optical axis direction. The coilspring 155 is stretched between one end of the second turning member 138and the attachment plate 139.

As shown in FIG. 25( a) and FIG. 25( b), the second turning member 138has the other end thereof formed with a projection 138 b projectingtoward the fourth transmission gear 29. The projection 138 b is engagedwith the second whorl groove 151 a. The second turning member 138 has aclockwise turning force on the rotation axis 138 a caused by the elasticrestoring force of the coil spring 155, whereby the projection 138 b isbiased toward the inner peripheral wall surface of the second whorlgroove 151 a.

Therefore, when a user rotates the vertical operation dial 28 to therebyrotate the fourth transmission gear 29, the projection 138 b of thesecond turning member 138 slides on the second whorl groove 151 a whilecontacting the inner peripheral wall surface of the second whorl groove151 a.

When the rotation of the vertical operation dial 28 brings theprojection lens system into the vertically central position indicated bythe solid line in FIG. 16, the projection 138 b of the second turningmember 138 is engaged by the biasing force of the coil spring 155 with arecess 151 b provided on the inner peripheral wall surface of the secondwhorl groove 151 a, as shown in FIG. 25( b).

The certain click-feeling will be given to the operation of the verticaloperation dial 28 by a collision made when the projection 138 b of thesecond turning member 138 engages with the recess 151 b of the secondwhorl groove 151 a. In order to further rotate the vertical operationdial 28 from this state, it is necessary to disengage the projection 138b of the second turning member 138 from the recess 151 b of the secondwhorl groove 151 a against the biasing force of the coil spring 155.This will give a certain resistance force to the rotation operation ofthe vertical operation dial 28.

According to the above liquid crystal projector device of the presentinvention, when adjusting the image projection position with the lensshift mechanism 2, a user can recognize, due to the click-feelings ofboth operation dials 24, 28, the horizontally and vertically centralpositions, which give a projection image with the maximum brightness.This allows adjustment of the image projection position with referenceto the horizontally and vertically central positions. Consequently, theimage projection position is adjusted more easily than conventionally.

Lamp Unit 7

As shown in FIG. 2, the lamp unit 7 providing a light source is attachedto the left end of the optical system holding case 30. As shown in FIG.26, the lamp unit 7 includes a reflector 71 having an ellipsoidalreflecting surface and joined to a rectangular frame 72. As shown inFIG. 34, the reflector 71 has a lamp bulb 170 providing the light sourcearranged at the focal position thereof. The lamp bulb 170 includes aluminous body enclosed inside a columnar glass tube 171. A lightemitting portion 172 enclosing the luminous body is spherical.

As shown in FIG. 26 and FIG. 27, the frame 72 has a rectangular opening72 a. A concave lens 80 is fitted in the opening 72 a. As shown in FIG.35( a), the concave lens 80 has a concave surface 80 a on the lightemergence surface. As shown in FIG. 35( b), the concave lens 80 has aconcavity 80 b formed only centrally on the light incidence surface.

As shown in FIG. 3, the lamp cooling fan 190 for cooling the lamp unit 7is arranged at the rear left end of the casing 1. As shown in FIG. 26and FIG. 27, the lamp unit 7 has the lamp cooling fan 190 facing sideformed with three air introduction openings 74 a, 73, 74 b forintroducing the air drawn from the lamp cooling fan 190 toward the lampbulb 170 shown in FIG. 34. Formed on the opposite side of the lamp unit7 is an air discharge opening 75 for discharging the air introduced fromthe three air introduction openings 74 a, 73, 74 b.

The lamp unit 7 is a user replacement part because its performancedeteriorates due to long use. This requires that the lamp unit 7 have anattachment structure that allows easy attachment/detachment. If the lampunit 7 is attached slantingly relative to the optical system holdingcase 30, then the brightness of the projection image lowers. Therefore,it is required that the lamp unit 7 have an attachment structure thatallows the lamp unit 7 to be easily attached/detached, as well asensuring that the lamp unit 7 can be positioned in a particular placerelative to the optical system holding case 30.

As shown in FIG. 29, in the projector device of the present invention,the lamp unit 7 can be attached to and detached from the left end of theoptical system holding case 30 by sliding along a plane perpendicular tothe optical axis of the optical system 3 disposed in the optical systemholding case 30.

The optical system holding case 30 has an upper wall and a lower wall ofthe left end thereof provided with two positioning holes 330 a, 330 band two positioning pins 331, 331 for positioning the lamp unit 7. Thetwo positioning holes 330 a, 330 b and two positioning pins 331, 331 areadjacently provided at a certain distance in the direction perpendicularto the optical axis of light emitted from the lamp unit 7.

As shown in FIG. 28 and FIG. 29, the frame 72 of the lamp unit 7 has,protruded upward from an upper surface thereof, two fitting pins 76, 76to fit into the two positioning holes 330 a, 330 b of the optical systemholding case 30, while, as shown in FIG. 26 and FIG. 27, the frame 72has a lower end thereof provided with two fitting holes 77, 77. The twopositioning pins 331, 331 of the optical system holding case 30 shown inFIG. 29 are to be fitted into both fitting holes 77, 77.

The fitting pins 76 have an outer diameter of 5 mm, and the positioningholes 330 a, 330 b have an inner diameter of 5.1 mm. The positioningpins 331 have an outer diameter of 4 mm, and the fitting holes 77 havean inner diameter of 4.1 mm.

As shown in FIG. 29 and FIG. 30, the optical system holding case 30 hasa sheet metal, rectangular frame-like flat spring member 340 attached tothe left end thereof. As shown in FIG. 30, the flat spring member 340 isattached to the left end of the optical system holding case 30 with hookholes 341, 341 provided on opposite upper ends engaged with hooks 333,333 protruded from inner surfaces of opposite side walls of the opticalsystem holding case 30, and with L-shaped bent portions 346, 346provided on opposite lower ends inserted in a slit groove 335 providedin the lower end of the optical system holding case 30.

The flat spring member 340 has a first flat portion 345 to contact anend surface 334 of the left end of the optical system holding case 30, asecond flat portion 344 projecting from the first flat portion 345toward the lamp unit 7, and inclined portions 342, 343 connecting thefirst flat portion 345 and second flat portion 344.

When the lamp unit 7 is attached to the optical system holding case 30,as shown in FIG. 29, the two fitting pins 76, 76 formed on the frame 72of the lamp unit 7 are inserted into the two positioning holes 330 a,330 b of the optical system holding case 30 from beneath the opticalsystem holding case 30.

As shown in FIG. 26, FIG. 27 and FIG. 29, taper machining is applied totips 76 a, 76 a of the two fitting pins 76, 76 of the frame 72 tothereby give the two fitting pins 76, 76 a tapered shape. Further, asshown in FIG. 32( a) and FIG. 32( b), one positioning hole 330 a of thetwo positioning holes 330 a, 330 b of the optical system holding case 30has a shape longer in the direction perpendicular to the optical axisdirection. Therefore, the two fitting pins 76, 76 of the frame 72 can beeasily inserted into the two positioning holes 330 a, 330 b of theoptical system holding case 30.

FIG. 32( a) shows the tips 76 a, 76 a of the two fitting pins 76, 76 ofthe frame 72 inserted in the two positioning holes 330 a, 330 b of theoptical system holding case 30. FIG. 33( a) shows the deformation of theflat spring member 340 in this state. In this state, an end surface 72 bof the frame 72 is only in contact with the second flat portion 344 ofthe flat spring member 340, and does not deform the flat spring member340.

When the lamp unit 7 is further inserted from this state, an end of thelamp unit 7 contacts the lower surface of the upper wall of the opticalsystem holding case 30, which receives the lamp unit 7, while the twopositioning pins 331, 331 of the optical system holding case 30 shown inFIG. 29 and FIG. 30 are fitted into the two fitting holes 77, 77 formedin the lower end of the frame 72 of the lamp unit 7 shown in FIG. 29. Asshown in FIG. 28, the lamp unit 7 is thus attached to the left end ofthe optical system holding case 30.

FIG. 31 and FIG. 32( b) show the lamp unit 7 attached to the left end ofthe optical system holding case 30. FIG. 33( b) shows the deformation ofthe flat spring member 340 in this state. In this state, as shown inFIG. 31 and FIG. 33( b), the end surface 72 b of the frame 72 pushes thesecond flat portion 344 of the flat spring member 340, whereby the flatspring member 340 is pressed between the end surface 72 b of the frame72 and the end surface 334 of the optical system holding case 30. Thiscauses the elastic deformation in the flat spring member 340.

The lamp unit 7 is pushed away from the optical system holding case 30by the elastic restoring force of this flat spring member 340. Becausethe fitting pin 76 is columnar and the first positioning hole 330 b iscircular, the centering effect due to the engagement of both causes thefitting pin 76 to move to a position where its central axis and thecenter of the first positioning hole 330 b stand in a line parallel tothe optical axis.

Consequently, as shown in FIG. 32( b), the lamp unit 7 is positioned, inthe direction along the optical axis, in a place where outer peripheralsurfaces of the fitting pins 76, 76 of the frame 72 are in contact withlamp unit 7 side end edges of the respective positioning holes 330 a,330 b of the optical system holding case 30, and, in the directionperpendicular to the optical axis, in a place where the central axis ofthe lower fitting pin 76 and the center of the lower positioning hole330 b stand in a line parallel to the optical axis.

According to the above attachment structure of the lamp unit 7, a usercan easily replace the lamp unit 7, and can incorporate the lamp unit 7into the device with high accuracy.

It is known that in light emission of the lamp bulb 170 shown in FIG.34, the temperature at the vertically upper side of the lamp bulb 170 ishigher than the temperature at the lower side thereof, which results inthe temperature difference between above and below the lamp bulb 170.This temperature difference between above and below is the greatest atthe light emitting portion 172 of the lamp bulb 170. In order to fullybring out the performance of the lamp bulb 170, it is necessary tomaintain the temperature of the lamp bulb 170 below a certaintemperature, as well as to cool the lamp bulb 170 such that thetemperature difference between above and below is held within a certainrange.

FIG. 39( a) shows air flows in the lamp unit 7 in the case where theliquid crystal projector device is set as shown in FIG. 1. As shown inFIG. 39( a), among the three air introduction openings 74 a, 73, 74 bfor introducing the air drawn from the lamp cooling fan 190 toward thelamp bulb 170, the first air introduction opening 74 a and second airintroduction opening 74 b are formed at opposite sides of a planepassing through a central axis of the lamp bulb 170 and perpendicular toa side wall of the lamp unit 7, and open toward the light emittingportion 172 of the lamp bulb 170. The third air introduction opening 73is formed between the first air introduction opening 74 a and second airintroduction opening 74 b, and open toward an end of the glass tube 171of the lamp bulb 170.

Therefore, the air drawn from the lamp cooling fan 190 shown in FIG. 3is forcibly separated by part of the side wall of the lamp unit 7intervening between the first air introduction opening 74 a and secondair introduction opening 74 b, so that the air introduced from the firstair introduction opening 74 a will flow above the light emitting portion172 of the lamp bulb 170, and the air introduced from the second airintroduction opening 74 b will flow below the light emitting portion 172of the lamp bulb 170. The air introduced from the third air introductionopening 73 will flow toward the end of the lamp bulb 170.

The liquid crystal projector device of the present invention can beattached with an attachment hardware to a ceiling or a vertical wallopposed to a screen with the bottom surface shown in FIG. 1 providing anattachment surface. The liquid crystal projector device of the presentinvention has functions for rotating by 180 degrees and verticallyflipping an image to be projected so as to allow the image to beprojected on a screen in a normal direction regardless of its setting.When the liquid crystal projector device is set by being hung from aceiling, its setting is vertically reversed from the setting shown inFIG. 1, and therefore projection images are rotated by 180 degrees.

When attached to a vertical wall opposed to a screen, the liquid crystalprojector device is set with the projection lens 20 shown in FIG. 1facing vertically upward or downward. Images can be projected forward bya mirror arranged at an inclination angle of 45 degrees relative to anoptical axis of image light projected from the projection lens 20. Whenit is set with the projection lens 20 facing vertically downward,projection images are vertically flipped.

FIG. 39( b) shows air flows in the lamp unit 7 in the case where theliquid crystal projector device is hung from a ceiling. In this settingstate, the air drawn from the lamp cooling fan 190 shown in FIG. 3 isforcibly separated by part of the side wall of the lamp unit 7intervening between the first air introduction opening 74 a and secondair introduction opening 74 b, so that the air introduced from the firstair introduction opening 74 a will flow below the light emitting portion172 of the lamp bulb 170, and the air introduced from the second airintroduction opening 74 b will flow above the light emitting portion 172of the lamp bulb 170. The air introduced from the third air introductionopening 73 will flow toward the end of the lamp bulb 170.

FIG. 39( c) and FIG. 39( d) show air flows in the lamp unit 7 in thecase where the liquid crystal projector device is attached to thevertical wall. In this setting state, the air drawn from the lampcooling fan 190 shown in FIG. 3 is forcibly separated by part of theside wall of the lamp unit 7 intervening between the first airintroduction opening 74 a and second air introduction opening 74 b, sothat the air introduced from the first air introduction opening 74 a andsecond air introduction opening 74 b will flow through both right andleft sides of the light emitting portion 172 of the lamp bulb 170. Theair introduced from the third air introduction opening 73 will flowtoward the end of the lamp bulb 170.

Therefore, the air drawn from the lamp cooling fan 190 shown in FIG. 3will not be vertically blown to the vertically lower surface of thelight emitting portion 172 of the lamp bulb 170 in any of the above foursettings. This prevents the low-temperature, vertically lower side ofthe light emitting portion 172 of the lamp bulb 170 from beingexcessively cooled. Consequently, the temperature difference between thevertically upper side and vertically lower side of the light emittingportion 172 of the lamp bulb 170 can be held within a certain rangeregardless of the setting of the device.

As shown in FIG. 36 through FIG. 38, the lamp unit 7 has attachedthereto a cover member 184 for covering the lamp unit 7 in order toprevent leak light. As shown in FIG. 37, the cover member 184 has oneside wall thereof provided with a first opening 186 at the opposedposition to the three air introduction openings 74 a, 73, 74 b of thelamp unit 7. As shown in FIG. 38, the opposite side wall of the covermember 184 is provided with a second opening 187 at the opposed positionto the air discharge opening 75 of the lamp unit 7, and has attachedthereto a channel housing 180 for constituting a channel for the airdischarged from the second opening 187.

As shown in FIG. 36 and FIG. 38, the channel housing 180 has a slit-likethrough hole 181 formed in a side wall thereof intersectingly with theflow of air flowing in the channel housing 180, while, as shown in FIG.37 and FIG. 38, the channel housing 180 has an air filter 182 of porousmaterial attached to the termination end thereof. The lamp bulb 170shown in FIG. 37 can explode due to long use. When the lamp bulb 170explodes, the gas enclosed in the lamp bulb 170 will be discharged. Theair filter 182 has a function for adsorbing particulates included in thegas to thereby prevent the particulates included in the gas from beingdischarged outside the device. A HEPA (High Efficiency Particulate Air)filter is used for the air filter 182.

FIG. 40( a) shows flows of air cooling the lamp bulb 170 in ordinaryuse. As shown in FIG. 40( a), the air drawn from the lamp cooling fan190 is introduced inside the lamp unit 7 through the three airintroduction openings 74 a, 73, 74 b of the lamp unit 7. The air havingcooled the lamp bulb 170 and become high in temperature will flowthrough the air discharge opening 75 at the opposite side and thechannel in the channel housing 180.

The high-temperature air will flow toward the termination end of thechannel housing 180, but its flow velocity is not so high that the aircannot pass through the air filter 182. The high-temperature air blockedby the air filter 182 will be discharged outside the channel housing 180by suction of the exhaust fan 191 through the through hole 181.

In contrast, FIG. 40( b) shows flows of gas enclosed in the lamp bulb170 in explosion of the lamp bulb 170. Because the gas is enclosed inthe lamp bulb 170 under high pressure, the internal pressure of thereflector 71 of the lamp unit 7 and the channel housing 180 willdrastically rise at the moment of explosion of the lamp bulb 170. Thiscauses the gas to burst into the channel in the channel housing 180.

The gas has a high flow velocity, and therefore will flow along thechannel in the channel housing 180, so that only a slight amount of thegas will be discharged outside the channel housing 180 from the throughhole 181 formed intersectingly with the channel in the channel housing180. Consequently, the gas will mostly flow toward the termination endof the channel in the channel housing 180, i.e. air filter 182.

The gas has also a high pressure, and therefore will not be blocked bythe air filter 182. The particulates included in the gas will beadsorbed by the air filter 182 while the gas is passing through the airfilter 182. Consequently, the purified gas will be discharged outsidethe channel housing 180 from the termination end of the channel housing180.

Therefore, the lamp unit 7 of the present invention makes it possible toprevent the particulates included in the gas enclosed in the lamp bulb170 from being discharged outside the device when the lamp bulb 170explodes without losing cooling efficiency for the lamp bulb 170.

As mentioned above, the liquid crystal projector device of the presentinvention employs the ellipsoidal reflector 71 as a reflectorconstituting the lamp unit 7 shown in FIG. 34. Conventional liquidcrystal projector devices have been using a lamp unit having a parabolicreflector. The lamp unit 7 having the ellipsoidal reflector 71 can givea smaller width of light emitted from the lamp unit 7 than that of alamp unit having a parabolic reflector, whereby the device can beminiaturized.

As shown in FIG. 5, the liquid crystal projector device of the presentinvention employs the integrator lens illumination system using the twointegrator lenses 31, 32. Therefore, as shown in FIG. 34, the concavelens 80 having the concave surface 80 a on the light emergence side isattached to the front of the lamp unit 7 in order to collimate the lightemitted from the lamp unit 7. As shown in FIG. 35( b), the concavity 80b is formed only centrally on the light incidence surface of the concavelens 80. The concave lens 80 has an effective diameter of 37 mm and afocal distance of 99 mm. The concavity 80 b has an effective diameter of10 mm and a focal distance of 48 mm.

As shown in FIG. 41, the light emitted from the concave lens 80 of thelamp unit 7 passes through cells 31 a constituting the first integratorlens 31, is imaged on respective cells 32 a of the second integratorlens 32 corresponding to the cells 31 a, and reach through the slitplate 33 to the polarization beam splitter 34.

FIG. 43( a) shows arc images of the lamp unit 7 imaged on thepolarization beam splitter 34, which are obtained by a computersimulation. FIG. 43( b) shows arc images of the lamp unit 7 imaged onthe polarization beam splitter 34 in the case of using a conventionalconcave lens without the concavity 80 b formed on the light incidencesurface instead of the concave lens 80 of the present invention.

When the lamp unit 7 having the ellipsoidal reflector 71 is used as anillumination system, the light emitted from the light emitting portion172 of the lamp unit 7 is reflected by the reflector 71, and condensedcentrally of the concave lens 80. Therefore, the light emitted from theconcave lens 80 at its central portion has a high brightness comparedwith the light emitted from the periphery.

FIG. 42( a) shows arc images 350 imaged on a plurality of centralconstituent cells 32 a of the second integrator lens 32 of the presentinvention. FIG. 42( b) shows arc images 350 imaged on the plurality ofcentral constituent cells 32 a of the second integrator lens 32 in thecase of using the conventional concave lens without the concavity 80 bformed on the light incidence surface instead of the concave lens 80 ofthe present invention.

As shown in FIGS. 43( a)(b), arc images imaged centrally on thepolarization beam splitter 34 are larger than arc images imaged on aplurality of peripheral constituent cells 32 a. As shown in FIGS. 42(a)(b), the arc images 350 are imaged on and beyond the respectivecentral constituent cells 32 a of the second integrator lens 32.

Each of the arc images 350 is caused to have distortion by theaberration caused by the reflector 71, concave lens 80 and firstintegrator lens 31 of the lamp unit 7. Therefore, each of the arc images350 is in the form of an approximate ellipse along a diagonal of therespective cells 32 a. In FIGS. 42( a)(b), hatching shows areas wherelight is blocked by the slit plate 33. Light is blocked by the slitplate 33 in areas of each of the arc images 350 not exposed from theslit apertures 33 a of the slit plate 33.

Therefore, it is important to reduce the amount of light blocked bythe-slit plate 33 in order to improve utilization efficiency of thelight emitted from the lamp unit 7. For this purpose, it is necessary toincrease the area of arc images 350 imaged on respective cells of thesecond integrator lens 32 corresponding to open areas of the slitapertures 33 a of the slit plate 33, as well as to increase the averagebrightness of the arc images 350.

As shown in FIG. 42( b), in the illumination system using theconventional concave lens, the arc images 350 are formed leaninglytoward the center of the second integrator lens 32 relative to therespective central constituent cells 32 a of the second integrator lens32. Therefore, the slit plate 33 blocks a larger amount of light, whichresults in a problem of a smaller amount of light reaching thepolarization beam splitter 34 at its central portion as shown in FIG.43( b).

Accordingly, the light irradiation position for the cells 32 a of thesecond integrator lens 32 was eagerly examined with computer simulationsand experiments. The result reveals that a larger amount of light isallowed to reach the polarization beam splitter 34 shown in FIG. 41 by,as shown in FIG. 42( a), moving the arc images 350 formed on therespective central constituent cells 32 a of the second integrator lens32 outward relative to the center of the second integrator lens 32 fromthe position shown in FIG. 42( b).

Accordingly, as shown in FIG. 35( b) and FIG. 41, the concavity 80 b isformed only centrally on the light incidence surface of the concave lens80. As shown in FIG. 41, the light incident on a central portion of theconcave lens 80 is slightly refracted outward from the central portionby passing through the concavity 80 b of the concave lens 80. The lighthaving passed via the concavity 80 b and concave surface 80 a throughthe concave lens 80 passes through the central constituent cells 31 a ofthe first integrator lens 31, and is imaged on the respective centralconstituent cells 32 a of the second integrator lens 32. Due to the lenseffect of the concavity 80 b of the concave lens 80, the arc imagesimaged on the respective central constituent cells 32 a of the secondintegrator lens 32 are formed in positions moved outward relative to thecenter of the second integrator lens 32 as shown in FIG. 42( a) from theposition shown in FIG. 42( b).

Thus, as shown in FIG. 43( a), a larger amount of light reaches thepolarization beam splitter 34 at its central portion than in theillumination system using the conventional concave lens shown in FIG.43( b). Consequently, utilization efficiency of the light emitted fromthe lamp unit 7 can be improved.

When the lamp unit 7 having the ellipsoidal reflector 71 is used toconstitute an illumination system, it is possible to improve utilizationefficiency of the light emitted from the lamp unit 7 without causing anincrease in the number of components because the concave lens 80 is anessential component. Further, the concavity 80 b has a simple shape,which makes it easy to work the concave lens 80. In addition, theoptical system 3 can be constructed using the two integrator lenses 31,32 having a plurality of cells 31 a, 32 a having a simple shape arrangedin the form of a matrix, which can reduce production costs more thanconventionally.

Cooling System 8

The cooling system 8 for cooling a plurality of optical componentsconstituting the image synthesizer 4 is, as shown in FIG. 4, disposedbelow the image synthesizer 4 shown in FIG. 3. The cooling system 8includes two cooling fans 81, 81 placed on the bottom surface of thelower half case 12 and a channel housing 82 constituting a channel forsending the outside air drawn from both cooling fans 81, 81 toward theliquid crystal panels 43 b, 43 g, 43 r and incidence polarizing plates41 b, 41 g, 41 r for the respective colors shown in FIG. 5. The channelhousing 82 has an upper surface thereof formed with air dischargeopenings 82 b, 82 b, 82 g, 82 g, 82 r, 82 r toward the liquid crystalpanels 43 b, 43 g, 43 r and incidence polarizing plates 41 b, 41 g, 41 rfor the respective colors. Both cooling fans 81, 81 are disposed in thechannel housing 82.

Both cooling fans 81, 81 have an air filter (not shown) attached to anoutside air intake opening thereof in order to prevent dust fromentering the inside of the device. The channel in the channel housing 82is provided with a temperature sensor (not shown) for detecting thetemperature of the outside air drawn from both cooling fans 81, 81.

As shown in FIG. 44, the air filter 83 is attached to each of thecooling fans 81, and each of the cooling fans 81 and the temperaturesensor 84 are connected to a microcomputer 89. The cooling fans 81 havea function of outputting a signal to change the on/off state each timeit rotates a predetermined number of times (hereafter referred to as arevolutions detection signal). The revolutions detection signal and atemperature detection signal output from the temperature sensor 84 arecaptured into the microcomputer 89.

Further connected to the microcomputer 89 are a fan drive circuit 85, amemory 86, and a warning means 88. The microcomputer 89feedback-controls the drive voltage to be given to the cooling fans 81based on the temperature detection signal output from the temperaturesensor 84 and the revolutions detection signal output from the coolingfans 81 such that the number of revolutions of the cooling fans 81 willbe a certain number of revolutions in accordance with an outside airtemperature T. The fan drive circuit 85 controls the drive voltage fordriving the cooling fans 81 in response to instructions from themicrocomputer 89.

As shown in FIG. 45, if the outside air temperature T is less than apredetermined temperature T1, for example, the cooling fans 81 aredriven at a predetermined number of revolutions r1. On the other hand,if the outside air temperature T exceeds a predetermined temperature T2,the cooling fans 81 are driven at a predetermined number of revolutionsr2 greater than the number of revolutions r1. If the outside airtemperature T is not less than T1 and not more than T2, they are drivenat a predetermined number of revolutions r3 obtained by the followingformula 1.r3=(r2−r1)/(T2−T1)×(T−T1)+r1  Formula 1:

Besides the predetermined temperatures T1 and T2 and predeterminednumbers of revolutions r1 and r2, the memory 86 shown in FIG. 44 storesa reference drive voltage V1 referred to when the cooling fans 81 aredriven at the predetermined number of revolutions r1 and a referencedrive voltage V2 referred to when the cooling fans 81 are driven at thepredetermined number of revolutions r2.

The microcomputer 89 detects the outside air temperature T based on thetemperature detection signal output from the temperature sensor 84. Whendetermining that the outside air temperature T is lower than thepredetermined temperature T1, the microcomputer 89 instructs the fandrive circuit 85 to give the cooling fans 81 the reference drive voltageV1, so that the cooling fans 81 will be driven at the reference drivevoltage V1.

The microcomputer 89 then detects the number of revolutions Rf of thecooling fans 81 based on the revolutions detection signal output fromthe cooling fans 81. When determining that the number of revolutions Rfis smaller than the predetermined number of revolutions r1, themicrocomputer 89 gives the fan drive circuit 85 instructions forchanging the drive voltage to be given to the cooling fans 81 to thevoltage (V1+ΔV) obtained by adding a predetermined voltage ΔV to thecurrent drive voltage V1. Consequently, the cooling fans 81 will bedriven at the drive voltage (V1+ΔV).

On the other hand, when determining that the number of revolutions Rf isgreater than the predetermined number of revolutions r1, themicrocomputer 89 gives the fan drive circuit 85 instructions forchanging the drive voltage to be given to the cooling fans 81 to thevoltage (V1−ΔV) obtained by subtracting the predetermined voltage ΔVfrom the current drive voltage V1. Consequently, the cooling fans 81will be driven at the drive voltage (V1−ΔV). When it is determined thatthe number of revolutions Rf is equal with the predetermined number ofrevolutions r1, the drive voltage of the cooling fans 81 are maintainedwithout being changed.

Repetition of the above steps maintains the number of revolutions of thecooling fans 81 at the predetermined number of revolutions r1.

Similarly, when the microcomputer 89 detects the outside air temperatureT based on the temperature detection signal output from the temperaturesensor 84, and determines that the outside air temperature T is higherthan the predetermined temperature T2, the microcomputer 89 instructsthe fan drive circuit 85 to give the cooling fans 81 the reference drivevoltage V2, so that the cooling fans 81 will be driven at the referencedrive voltage V2.

The microcomputer 89 then detects the number of revolutions Rf of thecooling fans 81 based on the revolutions detection signal output fromthe cooling fans 81. When determining that the number of revolutions Rfis smaller than the predetermined number of revolutions r2, themicrocomputer 89 gives the fan drive circuit 85 instructions forchanging the drive voltage to be given to the cooling fans 81 to thevoltage (V2+ΔV) obtained by adding the predetermined voltage ΔV to thecurrent drive voltage V2. Consequently, the cooling fans 81 will bedriven at the drive voltage (V2+ΔV).

On the other hand, when determining that the number of revolutions Rf isgreater than the predetermined number of revolutions r2, themicrocomputer 89 gives the fan drive circuit 85 instructions forchanging the drive voltage to be given to the cooling fans 81 to thevoltage (V2−ΔV) obtained by subtracting the predetermined voltage ΔVfrom the current drive voltage V2. Consequently, the cooling fans 81will be driven at the drive voltage (V2−ΔV). When it is determined thatthe number of revolutions Rf is equal with the predetermined number ofrevolutions r2, the drive voltage of the cooling fans 81 are maintainedwithout being changed.

Repetition of the above steps maintains the number of revolutions of thecooling fans 81 at the predetermined number of revolutions r2.

When the microcomputer 89 detects the outside air temperature T based onthe temperature detection signal output from the temperature sensor 84,and determines that the outside air temperature T is between thepredetermined temperature T1 and predetermined temperature T2, thepredetermined number of revolutions r3 at which the cooling fans 81 areto rotate in the outside air temperature T is first calculated based onthe formula 1. The microcomputer 89 then calculates a reference drivevoltage V3 to be given to the cooling fans 81 with reference to thepredetermined numbers of revolutions r1 and r2, reference drive voltagesV1 and V2, and calculated predetermined number of revolutions r3, andinstructs the fan drive circuit 85 to give the cooling fans 81 thereference drive voltage V3. Consequently, the cooling fans 81 will bedriven at the reference drive voltage V3. For example, the referencedrive voltage V3 is calculated by the following formula 2.V3=(V2−V1)/(r2−r1)×(r3−r1)+V1  Formula2:

The microcomputer 89 then detects the number of revolutions Rf of thecooling fans 81 based on the revolutions detection signal output fromthe cooling fans 81. When determining that the number of revolutions Rfis smaller than the predetermined number of revolutions r3, themicrocomputer 89 gives the fan drive circuit 85 instructions forchanging the drive voltage to be given to the cooling fans 81 to thevoltage (V3+ΔV) obtained by adding the predetermined voltage ΔV to thecurrent drive voltage V3. Consequently, the cooling fans 81 will bedriven at the drive voltage (V3+ΔV).

On the other hand, when determining that the number of revolutions Rf isgreater than the predetermined number of revolutions r3, themicrocomputer 89 gives the fan drive circuit 85 instructions forchanging the drive voltage to be given to the cooling fans 81 to thevoltage (V3−ΔV) obtained by subtracting the predetermined voltage ΔVfrom the current drive voltage V3. Consequently, the cooling fans 81will be driven at the drive voltage (V3−ΔV). When it is determined thatthe number of revolutions Rf is equal with the predetermined number ofrevolutions r3, the drive voltage of the cooling fans 81 are maintainedwithout being changed.

Repetition of the above steps maintains the number of revolutions of thecooling fans 81 at the predetermined number of revolutions r3.

If the air filters 83 of the cooling fans 81 are clogged due to longuse, an insufficient amount of outside air is drawn from the cooling fan81, while a certain amount of air is discharged outside the device fromthe exhaust fan 191 shown in FIG. 3. This gives a negative pressure inthe channel housing 82, which in turn gives a small load when thecooling fans 81 rotate. In this case, the cooling fans 81 will receive areduced drive voltage although the number of revolutions will notincrease because the cooling fans 81 are driven at a predeterminednumber of revolutions determined depending on the outside airtemperature T.

Accordingly, when the cooling fans 81 are driven at a predeterminednumber of revolutions determined depending on the outside airtemperature T, the microcomputer 89 compares an actual drive voltage Vfgiven to the cooling fans 81 with the reference drive voltage Vref,determines that the air filters 83 are clogged when the differencebetween both voltages is a certain value or more, gives a warning thatthe air filters 83 are clogged, and performs a protection operation ofshutting off or reducing the power to be supplied to the lamp unit 7lower than usual.

In FIG. 46, the solid line indicates a relationship between the numberof revolutions of the cooling fans 81 and the reference drive voltageVref, and the dashed line indicates a relationship between the number ofrevolutions of the cooling fans 81 and the drive voltage at which it isdetermined that the air filters 83 are clogged. The warning operationand protection operation will be performed when the difference betweenthe reference drive voltage Vref and actual drive voltage is apredetermined value V4 or more as shown in FIG. 46.

FIG. 47 shows a control procedure to be performed by the microcomputer89 during clogging detection for the air filters 83. First, in step S1,the number of revolutions Rf of the cooling fans 81 are detected by therevolutions detection signal output from the cooling fans 81. Based onthe number of revolutions Rf, the drive voltage Vf to be given to thecooling fans 81 are feedback-controlled such that the cooling fans 81are driven at a predetermined number of revolutions determined dependingon the outside air temperature T. Then, in step S2, the drive voltage Vfis detected when the cooling fans 81 rotate at the predetermined numberof revolutions. In step S3, an inquiry is made as to whether or not thedifference between the reference drive voltage Vref determined dependingon the predetermined number of revolutions and the drive voltage Vf isgreater than the predetermined value V4. If the inquiry in step S3 isanswered in the negative, then step SI follows to continue the feedbackcontrol of the drive voltage Vf to be given to the cooling fans 81.

If the inquiry in step S3 is answered in the affirmative, then step S4follows to give a warning that the air filters 83 are clogged. Thewarning is given, for example, by lighting or flashing at least one of aplurality of warning lights constituting the warning portion 15 shown inFIG. 1. Alternatively, a message that the air filters 83 are clogged maybe displayed on a forward projection screen.

Step S5 follows thereafter to shut off or reduce the power to besupplied to the lamp unit 7 lower than usual in order to suppress heatgeneration of a heat source of the lamp unit 7 to thereby perform theprotection operation for preventing temperature rise of the liquidcrystal panels 43 b, 43 g, 43 r and incidence polarizing plates 41 b, 41g, 41 r for the respective colors shown in FIG. 5 to end the processing.

Step S5 may perform a protection operation of increasing the number ofrevolutions of the cooling fans 81 higher than usual in order tosuppress the reduction of the outside air drawn from the cooling fans 81due to clogging of the air filters.

According to the above driving method for the cooling fans 81, thecooling fans 81 are driven at a predetermined number of revolutionsdetermined depending on the outside air temperature T, and therefore thecooling fans 81 draw an approximately constant amount of outside airregardless of individual differences of the cooling fans 81. Therefore,there is no variation in the cooling effect of the cooling system 8between liquid crystal projector devices, which can always provide aconstant cooling effect regardless of individual differences of thecooling fans 81.

In addition, clogging of the air filters 83 can be detected by comparingthe actual drive voltage Vf of the cooling fans 81 with the referencedrive voltage Vref, which eliminates the necessity of a temperaturesensor for detecting the temperature of the liquid crystal panels 43 b,43 g, 43 r and incidence polarizing plates 41 b, 41 g, 41 r for therespective colors shown in FIG. 5 unlike in conventional devices.

The present invention is not limited to the foregoing embodiment but canbe modified variously by one skilled in the art without departing fromthe spirit of the invention as set forth in the appended claims. Forexample, as shown in FIG. 26, while the lamp unit 7 of the presentembodiment has the third air introduction opening 73 provided betweenthe first and second air introduction openings 74 a, 74 b and openedtoward the end of the lamp bulb 170, the third air introduction opening73 may be excluded if a sufficient cooling effect can be provided.

1. A projector device comprising: a lamp unit providing a light source;a cooling fan for cooling the lamp unit; and an optical system forgenerating color image light with the lamp unit providing the lightsource, the lamp unit comprising a columnar lamp bulb having a luminousbody enclosed therein; and a reflector for reflecting light emitted fromthe lamp bulb toward the optical system, wherein the projector device iscapable of taking a plurality of set postures including a first setposture where the lamp bulb of the lamp unit extends approximatelyhorizontally, and a second set posture where the projector device isrotated around an axis of the lamp bulb by 90 degrees from the first setposture, wherein a first air introduction opening and a second airintroduction opening are provided in a side wall of the lamp unitopposed to the cooling fan and at opposite sides of a plane including acentral axis of the lamp bulb and perpendicular to the side wall, thefirst air introduction opening and the second air introduction openingintroducing air in a direction parallel to the plane, and air dischargedfrom the cooling fan is blown to the lamp bulb through the both airintroduction openings, and wherein the air discharged from the coolingfan is separated by a part of the side wall between the first airintroduction opening and the second air introduction opening so that airintroduced from the first air introduction opening flows above the lampbulb in a space inside the reflector with a boundary located on theplane and air introduced from the second air introduction opening flowsbelow the lamp bulb in a space inside the reflector with a boundarylocated on the plane.
 2. The projector device according to claim 1,wherein the first air introduction opening and the second airintroduction opening are open toward a light emitting portion of thelamp bulb, and a third air introduction opening open toward an end ofthe lamp bulb is provided between the first and second air introductionopenings in the side wall.